In order to promote the development of bone substances at bone defects, it is known to cover the defect location with a foil so as to hold the soft tissue with the foil from growing into the defect location. It is further known to fill the region in which new bone growth is to occur with a granulate and to cover the volume thereof with a foil. The granulate, usually hydroxyapatite, has a "place holding" function in which the bone growth can occur and the foil is usually composed of a textile material of such fibers as have been long used for the stitching of wounds. This fabric has a protective effect when positioned over the bone defect and held in place by stitching, for example.
The fiber structure at the edges of the fabric, as a result of cutting operations, for example, during a surgical procedure, and the mechanical properties of the textile material, especially its elasticity, are not fully ideal for many applications.
In EP 622 052 A1, a process for forming a foil is described to promote bone growth in the dental field. An image of the defect location is taken, usually digitally, and a model is formed, whereby a stiff foil can be shaped to the model, i.e. given the desired shape. The foil material used was, for example, shape-stable titanium in a thickness of say 0.3 mm.
German patent 43 02 709 C1 deals with a covering of a bone growth region provided with a bone-growth promoter like hydroxyapatite granules, in which the membrane is bendable and ductile and requires a stiffening in the form of a rigid titanium foil of a thickness of 0.3 to 1 mm with perforations.
Titanium metal is also used for dental impressions, bone nails, plates and rails for surgical purposes. The tolerance to titanium is high and X-rays are not obscured because the wall thicknesses of the titanium articles utilized need not be particularly great.